TY  - JOUR
A1  - Zilliges, Yvonne
A1  - Kehr, Jan-Christoph
A1  - Meissner, Sven
A1  - Ishida, Keishi
A1  - Mikkat, Stefan
A1  - Hagemann, Martin
A1  - Kaplan, Aaron
A1  - Börner, Thomas
A1  - Dittmann-Thünemann, Elke
T1  - The cyanobacterial hepatotoxin microcystin binds to proteins and increases the fitness of microcystis under oxidative stress conditions
JF  - PLoS one
N2  - Microcystins are cyanobacterial toxins that represent a serious threat to drinking water and recreational lakes worldwide. Here, we show that microcystin fulfils an important function within cells of its natural producer Microcystis. The microcystin deficient mutant Delta mcyB showed significant changes in the accumulation of proteins, including several enzymes of the Calvin cycle, phycobiliproteins and two NADPH-dependent reductases. We have discovered that microcystin binds to a number of these proteins in vivo and that the binding is strongly enhanced under high light and oxidative stress conditions. The nature of this binding was studied using extracts of a microcystin-deficient mutant in vitro. The data obtained provided clear evidence for a covalent interaction of the toxin with cysteine residues of proteins. A detailed investigation of one of the binding partners, the large subunit of RubisCO showed a lower susceptibility to proteases in the presence of microcystin in the wild type. Finally, the mutant defective in microcystin production exhibited a clearly increased sensitivity under high light conditions and after hydrogen peroxide treatment. Taken together, our data suggest a protein-modulating role for microcystin within the producing cell, which represents a new addition to the catalogue of functions that have been discussed for microbial secondary metabolites.
Y1  - 2011
U6  - https://doi.org/10.1371/journal.pone.0017615
SN  - 1932-6203
VL  - 6
IS  - 3
PB  - PLoS
CY  - San Fransisco
ER  -